[s_tec]

Right, that is correct. To understand how that works, you have to realize that there is no such thing as an "absolute voltage", only the voltage difference between two wires.

In a breaker box, one wire (white) gets tied to ground, and the other wire (black or red) goes between +170 (relative to ground) and -170 (relative to ground). The black and red wires are 180 degrees out of phase, so when the black wire is at +170, the red wire is at -170. This gives a 340V peak difference between the black and red wires, which averages to 240V. You get your normal 120V outlet power between the hot legs and ground/neutral, and you get your 240V dryer & water heater power between the two hot legs themselves.

So, in a normal outlet, we can safely say that one wire is "more positive" than another, and that this flip-flops through time. When we look at voltages relative to ground, though, one wire stays put at 0V while the other goes between +170 and -170. It's just a question of where you put your reference frame.

[ars]

This is not what you said in the other post. You are confusing people, and you should edit it.